Cam action screw driver



Feb. 27, 1951 G. F. CRUMMEY 2,543,441

CAM ACTION SCREW DRIVER Filed March 11, 1947 a mg 22 ATTORNEY PatentedFeb. 27, 1951 UNHED STATES ii Tfi FFICE 2 Claims.

Thi invention relates to care action screw tools, and more particularlyto a hand-operated tool for seating and unseating tight or mutilatedscrews.

One object of the present invention is to provide a device of the abovenature including a driving shank having a blade for engaging in a screwslot and in which said shank is provided at its upper end with a crosspin and an adaptor which may be detachably held in the lower end of thehandle;

A further object is to provide a tool of the above nature in which thehandle is provided with a coiled spring located in an exterior groovenear the lower end of said handle for pressing inwardl resiliently upona radial locking pin which is located in an elongated groove in outsideof the adaptor.

A further object is to provide a tool of the above nature, having ametal handle on which are a pair of l-shaped oppositely arranged earnsat the lower end thereof for engaging the cross pin for turning theshank selectively in either direction whenever said handle is struck onits top by a hammer.

A further object is to provide a tool of the above nature, which will besimple in construction, inexpensive to manufacture, easy to install andmanipulate, compact, ornamental in appearance, and very efficient anddurable in use.

With these and other objects in view, there has been illustrated on theaccompanying drawing one form in which the invention may conveniently beembodied in practice.

In the drawing,

Fig. 1 represents a side view of the cam action screw tool.

Fig. 2 is a View of the same, taken at right angles from the view ofFig. 1, and showing a longitudinal section through the lower end of thehandle, as it appears when used for removing a tight screw from asocket.

Fig. 3 is a longitudinal side sectional View, of the upper portion ofthe adaptor, and a tool shank on which it is mounted.

Fig. 4 is a cross sectional view on a larger scale, taken along the linell of Fig. 2, looking downwardly.

Fig. 5 is a perspective view on a larger scale of the coiled spring forretaining the locking pin in operating position within the groove of theadaptor.

Fig. 6 is a cross sectional view on a larger scale, taken along the line5-5 of Fig. 2, looking upwardly.

The present invention is especially adapted for use for loosening tightscrews where the screw slot is paint-filled or mutilated. It is alsoadapted to be used for removing screws or bolts having broken ormutilated heads without the use of taps and drills.

By means of the present invention, the former disadvantages have beenovercome.

Referring now to the drawings in which like reference numerals denotecorresponding parts throughout the several views, the numeral illindicates a solid metal handle, preferably hexagonal in shape, andhaving near the bottom portion thereof an annular exterior groove llwithin which is seated a coiled spring having'alrleast one turn. Thecoiled spring i2 is adapted to be pressed inwardly against the head of alock pin l3 having a reduced interior rounded shank [3a.

The handle ill has a reduced lower end l i provided with a drilledsocket 15 having a radial hole 5 at the inside of the groove H forreceiving the shank i305 of the lock pin iii. The bottom end of thereduced section ill of the handle id is provided with a pair of l-shaped cams ll, l8 having flat bottoms l9 and between which are a pairof V-shaped cam slots 28, 2| of gothic arch shape.

The screw driver has a shank 22 provided with a flat bottom blade 23,and said shank 22 i provided near its upper end with a horizontaldriving pin 24 having chamiered ends 25, 26. The pin 24 is driventhrough an aperture 21 in the upper portion of the shank 22, and alsothrough a pair of aligned side holes 3%, M in an adaptor 28, which isdetachably seated in the socket H3 in the lower end of the handle I0.

The adaptor 28 is provided with an interior cylindrical socket 255 forfitting tightly over the upper end of the shank 22the lower end of saidadaptor 28 being chamiered at 32.

In order to permit the adaptor 28 and the shank 22 to be readily removedfrom the handle iii whenever desired, as for the purpose of inserting adifferent shank therein, provision is made of an elongated upper groove33 in the adaptor 28, said groove having bevelled upper and lower ends3%, 35. The width of the groove 33 is the same as the maximumlongitudinal throw of the cam handle ll).

Operation When it is desired to use the tool, assuming the pin 24engages one of the cams 20, 2|, the heavy handle it] which is heldfirmly in one hand, will be struck a blow with a hammer held in the Vteior annular groove adjacent other hand. Through the medium of thecross pin 24 and. cams 20, 2i, a torque force will be transmitted to theshank 22 for rotating the screw S or other object engaged by the shankblade 23. In other words, when the handle in descends under the force ofthe hammer blow, the two oppositely inclined edges of the cam members20, 2! will exert a wedging action on the oppositely disposed sides ofthe shank pin 24 and produce a very strong turning action upon the screwS.

One advantage of the present invention is that the tool is applicable toboth right-hand or 1efthand threaded screws, and that a considerablenumber of shanks of diiferent shapes and sizes may be interchangeablycarried in the same handle, as the adaptors have uniform exteriordimensions.

While there has beendisclosed in this specification one form in whichthe invention may be embodied, it is to be understood that this form isshown for the purpose of illustration only, and that the invention isnot to be limited to the specific disclosure, but may be modified andembodied in various other form without departing from its spirit Inshort, the invention includes all the modifications and embodimentscoming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, andfor which it is desired to secure Letters Patent, is:

1. In a cam action screw driving tool, a handle having an interiorsocket opening out of the lower end thereof, said handle having an e:-

the upper en of said socket, said groove being connected with saidsocket by of a transverse hole, a headed locking pin slidably mounted insaid hole and having a roan-ed inner end, a coiled spring fitted intosaid groove for pressing inwardly upon the head of locking pin, a 5Csaid handle will have a limited up and down movement with respect tosaid adaptor and shank, the upper end wall of said elongated groovebeing beveled to permit said rounded end pin to be manually forcedupwardly beyond said adaptor to release said adaptor and shank from saidhandle, said handle having a pair of V-shaped oppositely disposed camlugs at its lower end, and a horizontal pin extending through andconnecting said adaptor and said shank, said horizontal pin havingprojecting ends for engagement by said lugs to rotate said shank whenthe handle is struck by a hammer.

2. In a cam action screw driver, a handle having a socket opening out ofits lower end, a screwengaging shank, an adaptor having a lower endsocket embracing said screw-engaging shank, said adaptor beinginsertable loosely into said handle socket and having an elongatedexterior groove adjacent its upper end, the upper extremity of saidgroove being beveled, a slidaole inwardly spring pressed pin rounded atits inner end passing through said handle an adapted to seat in saidgroov to cietachably lock said adaptor and shank in said handle, saidhandle having a pair oi" V-shapcd oppositely disposed cam lugs at itslower end and said adaptor having a ho izontal pin extending throughsaid adaptor and said shank and having projecting ends for engagement bysaid lugs to rotate said shank when the handle is struck by a hammer.

GEORGE CRUMMEY.

REFERENCES CITED The following references are of record in the nle ofthis patent:

UNITED STATES PATENTS France June 29, 1936

